New Technique Offers Easy, Inexpensive Spray-On Solar Power

Researchers with the Department of Electrical and Computer Engineering at the University of Toronto and IBM Canada’s Research and Development Centre have invented a new way to spray solar cells onto flexible surfaces using minuscule light-sensitive materials known as colloidal quantum dots (CQDs). The invention is being touted as a major step toward making spray-on solar cells easy and inexpensive to manufacture.

Solar-sensitive CQDs printed onto a flexible film could be used to coat surfaces ranging from patio furniture to an airplane wing. A surface the size of a car roof wrapped with CQD-coated film would produce enough energy to power three 100-W light bulbs or 24 compact fluorescents.

Until now, it was only possible to incorporate light-sensitive CQDs onto surfaces through batch processing. This new technique, called sprayLD, blasts a liquid containing CQDs directly onto flexible surfaces, similar to the process of printing a newspaper by applying ink onto a roll of paper. This roll-to-roll coating method makes incorporating solar cells into existing manufacturing processes much simpler. The sprayLD method can be used on flexible materials without any major loss in solar-cell efficiency, the researchers reported in two recently published papers.

The sprayLD device (pictured) was built with parts that are readily available in hardware and art supply stores.